Ibn al-Bann1321) is the author of one of the four extant of the unfinished zq (fl. Tunis and Marrakesh ca. 1193j accessible for the computation of planetary longitudes. The present paper studies some modifications of the structure of the tables the purpose of which is to make calculations easier. The tables of the planetary and lunar equations of the centre are ' appears as a clever adapter, who displays a clear ingenuity allowing him to introduce formal modifications which give his (...) work an appearance of novelty which does not correspond to reality. (shrink)

An Andalusian tradition of zījes seems to have been predominant in the Maghrib due to the popularity of the zīj of Ibn Is[hdotu]āq al-Tūnisī and derived texts compiled in the fourteenth century. This tradition computed sidereal planetary longitudes and allowed the calculation of tropical longitudes by using trepidation tables based on models designed in al-Andalus by Abū Is[hdotu]āq ibn al-Zarqālluh. This tradition also used Ibn al-Zarqālluh's model to calculate the obliquity of the ecliptic, which implied that this angle had a (...) cyclical period of oscillation between a maximum of 23;53° and a minimum of 23;33°: after reaching this minimum value the obliquity of the ecliptic was bound to increase. This paper argues that some new Maghribi sources give information on observations made in the Maghrib in the fourteenth and beginning of the fifteenth centuries that imply that precession had increased beyond the limits allowed by the Zarqāllian trepidation theory, while the obliquity of the ecliptic had diminished below the level accepted by astronomers who followed Ibn al-Zarqālluh. This explains the introduction in the Maghrib of Eastern zījes, which computed directly tropical longitudes and did not accept the cyclical variation of the obliquity. Information about observations of dawn and twilight made both in Egypt and in the Maghrib in the fourteenth and fifteenth centuries is also presented. (shrink)

A social history of Andalusi exact sciences should deal with scientific schools, teaching, travels to the East, patronage and scientific professions. I claim that such a social history of Andalusi science is almost impossible because of the lack of sources.

Tras una rápida revisión de los escasos datos conocidos sobre la vida y la obra de Ibn Abī l-Riŷāl , se analiza el contenido de su Urŷūza fī aḥkām al-nuŷūm comparándola con su célebre al-Kitāb al- Barī‘ fī aḥkām al-nuŷūm concluyéndose que se trata de dos obras independientes y que la Urŷūza no es un resumen del Barī‘. El trabajo continúa con datos biobibliográficos del historiador, matemático y astrólogo Ibn Qunfuḏ al-Qusanṭīnī , autor de un comentario a la Urŷūza de (...) Ibn Abī l-Riŷāl dedicado a Abū Bakr b. Abī Muŷāhid Gazī Ibn al-Kās, visir de los sultanes meriníes Abū Fāris y Abū Zayyān . La obra parece haber sido redactada durante el breve reinado de este último y antes de la deportación del dedicatario a Mallorca en 1375. Se analiza el contenido del comentario, las fuentes citadas en el mismo, las técnicas astrológicas utilizadas tanto por Ibn Qunfuuḏ como por Ibn Abī l-Riŷāl y el uso, por parte del comentarista de un zīŷ derivado del de Ibn Isḥāq. El artículo termina con un comentario detallado de los horóscopos contenidos en la obra de los que uno corresponde al equinoccio vernal del año 571 de JC, en el que se produjo una conjunción de Saturno y Júpiter que anunció el advenimiento del Islam, mientras que los once restantes constituyen una historia astrológica del Marruecos meriní entre 1348 y 1366. Dos de ellos habían sido publicados en un artículo anterior. En lo que respecta a los nueve restantes, en seis de ellos se identifica el sujeto o acontecimiento al que aluden, quedando tres por identificar. (shrink)